Covariate-Specific Estimation of the Sensitivity to the Early Disease Stage in Diagnostic Tests

Within the three-class ROC analysis framework, we address the problem of making inferences about a true class fraction (TCF), given the remaining two. More precisely, we propose a procedure to esti- mate the covariate-specific TCF2, i.e., the covariate-specific probability of correct classification at the so-called early stage, when the values for the true class fractions at first and third classes are fixed. An application to a real dataset is also presented.